WO2002059071A1

WO2002059071A1 - Process for producing alkanedicarboxylic acid

Info

Publication number: WO2002059071A1
Application number: PCT/JP2002/000513
Authority: WO
Inventors: Masatsugu Kawase; Yasuhiro Murozono
Original assignee: Asahi Kasei Kabushiki Kaisha
Priority date: 2001-01-25
Filing date: 2002-01-24
Publication date: 2002-08-01
Also published as: KR20030074738A; US20040073061A1; CN1221508C; CA2434894C; ATE486837T1; EP1354866B1; JP4004407B2; BR0206659B1; MY136690A; TWI238157B; US7019167B2; UA73646C2; JPWO2002059071A1; EP1354866A1; BR0206659A; DE60238176D1; KR100527655B1; CN1487914A; CA2434894A1; EP1354866A4

Abstract

A process for producing an alkanedicarboxylic acid by oxidizing a cycloalkanol and/or cycloalkanone with an aqueous nitric acid solution, which comprises using a heat-insulated reactor comprising a feed nozzle with which the cycloalkanol and/or cycloalkanone can be fed at a linear velocity of 8x10-2 m/sec or higher and a mixing device.

Description

Production method of boric acid

The present invention relates to a method for producing an alkanedicarboxylic acid by oxidizing a cycling alcohol or Z or a cycling alcohol with nitric acid. More specifically, a cycloalkyl alcohol and / or a cycloalkanol are oxidized in an adiabatic reactor using nitric acid.

The present invention relates to a method for producing an alkanedicarboxylic acid, which produces a high yield of an alkanedicarboxylic acid regardless of the temperature of the adiabatic reactor.

Background art

It has been known that it is possible to oxidize alkanols and / or alkanols to nitric carboxylic acids at elevated temperatures using nitric acid. Also known is a method for producing an alkanedicarboxylic acid by nitrating nitric acid and / or Z at an adiabatic reactor to produce an alkanedicarboxylic acid. For example, Japanese Patent Publication No. 439-19529 states that the starting material is mixed vigorously with 40 to 70% nitric acid in an amount of 80 to 400 times the volume, and during the reaction, the reaction temperature increases by 2%. Adjust the amount of nitric acid so that it does not exceed 5 ° C, and allow the reaction to proceed at a temperature of 45 to 90 ° C under normal pressure or pressure and discharge from the reaction zone after a residence time of 4 minutes or less. The reaction mixture thus obtained is separated from nitric oxide, and the concentration of nitric acid is raised again to a height approximately equivalent to the concentration in the reaction zone by evaporation of water from the reaction mixture, and alkanedicarboxylic acid is removed from a part of the reaction mixture. Separation in the usual way, combining the mother liquor with the rest of the reaction mixture, vigorously mixing this combined mixture with fresh starting materials, and returning to the reaction zone, cycling at elevated temperature Cycloalkanol, cycloalkanone, or cycloalkylamine And / or the ω-hydroxylalkane force having at least 4 carbon atoms rubonic acid, the continuous formation of alkynedicarboxylic acid by oxidizing ratatotone or tetrahydrofuran of this to-hydroxylalkanecarboxylic acid with nitric acid The manufacturing method is shown. In this, nitric acid (ie nitric acid sent to the circuit and / or freshly supplied nitric acid) is mixed with the starting material in the reaction zone and introduced into the reaction zone. And a starting material (ie, cycloalkanol, cycloalkanone, or cycloalkylamine and Z or an ω-hydroxylalkanecarboxylic acid having at least 4 carbon atoms, a lactone of the ω-hydroxylalkanecarboxylic acid or tetrahydrofuran) It is stated that it is desirable to carry out as short as possible. It is stated that it is preferable to mix the starting materials using a injector, a mixing nozzle or a turbine mixer under conditions such that the starting material is transparently dissolved after at least 5 seconds. It is disclosed that especially in the case of oxidation of neck hexanol and neck hexanone, efforts should be made to obtain a clear solution within 0.05-0.1 seconds after mixing. The reason is that if the mixing is not performed in a short time, the temperature in the reaction zone locally increases, and the yield of alkanedicarboxylic acid decreases. However, even with the mixing time described in JP-B-43-195529, the yield of alkanedicarboxylic acid is not always high. This indicates that the mixing time defined in Japanese Patent Publication No. 439-19529 is not appropriate.

It is also known in the literature of I that, in the reaction of nitric acid oxidation of cyclohexanol and / or cyclohexanone to produce adipic acid, the yield of adipic acid obtained at high temperatures decreases. Preparation of adipic acid by oxidation of cyclohexanol and cyclohexanone with nitric acid (preparation of adipic acid by nitration of cyclohexanol and cyclohexanone), WJ VAN ASSELT and DW VAN KREVELEN, Rec. Tra. Chem. , 82, 51-67, 429-437, 438-449 (1963) show that the results of a batch acid reaction test in a cylindrical vessel equipped with a magnetic stirrer and a cooling jacket indicate that high temperatures, especially 60 ° Above C, it shows that the adipic acid yield decreases even when Cu is present as a catalyst.

Therefore, despite the fact that the residence time or the mixing time is specified to be extremely short in Japanese Patent Publication No. 439-19529, the reaction is carried out at a temperature of 45 to 90 ° C under normal pressure or under pressure. It is going to progress. Furthermore, in the example of Japanese Patent Publication No. 439-195229, the outlet temperature of the thermal break reactor is specified as 70 ° C.

Preparation, adipic acid by oxidation of cyclohexanol and cyclohexanone with nitric acid, WJ VAN ASSELT and DW VAN KREVELEN, Rec. Tra. Chem., 82, 51-67, 429-437, 438-449 (1963). Calculations using the reaction rate of adipic acid to adipic acid also reveal that the nitric acid concentration required to achieve the same adipic acid yield increases with decreasing temperature.

This indicates that the conventional technique increases the adipic acid yield at low temperatures but increases the amount of nitric acid used for oxidation. That is, the method disclosed in JP-B-43-19529 described above is consumed because nitric acid is used to oxidize the alkanol and Z or cycloa / lecanone at a low temperature of 45 to 90 ° C. The problem is that the amount of nitric acid increases.

Japanese Patent Publication No. 48-21088 discloses a method for reducing nitric acid consumption. The publication discloses a method in which cycloalkanol and Z or cycloalkanone are converted to alkanedicarboxylic acids by liquid-phase nitric acid oxidation, which consumes essentially only a small amount of nitric acid. That is, according to a method for producing alkyne dicarponic acid by liquid-phase nitric acid oxidation of a reaction component selected from the group consisting of cycloalkanone and cycloalkanone, which has an improvement in reducing the consumption of nitric acid, Contact with nitric acid at a temperature of 90-140 ° C. in the presence of one panadium catalyst; 0.30-0.60% by weight of oxidized copper; 0.01-1.50% by weight of oxidized copper Circulating at least a portion of the reaction mixture containing the reduced vanadium and the nitrate reduction product having an average oxygen to nitrogen ratio greater than 0.5, wherein the weight ratio of circulating stream to reactants is 200 to 1 300, and maintaining the product of the weight ratio and the oxidized vanadium concentration to be 30 to 60, and then recovering the alkanedicarboxylic acid. I have. The circulation here is different from the large circulation flow of the aqueous nitric acid solution in the present invention described below, and is circulation only in the reaction system. In the present specification, this is defined as a circulation stream of the reaction system.

Further, Japanese Patent Publication No. 48-21088 discloses that a suitable mixing device, such as a draft tube mixer (draf t-tube-mixer) may be used to facilitate flow mixing. However, with this method, It is necessary to set the weight ratio of the circulation stream of the reaction system to the reaction components to be as large as 200 to 130,000. When the amount of circulation in the reaction system increases, a large pump, piping and reactor considering the pressure loss are required to secure a sufficient amount of circulation, which is disadvantageous in both equipment costs and power proportional costs.

As listed above, techniques for oxidizing cycloalkanol and / or cycloalkanone to alkanedicarboxylic acid using nitric acid are known.However, in order to increase the yield of alkanedicarboxylic acid, these are used in the reaction zone. The temperature of the reaction must be 90 ° C or lower, or even at a temperature exceeding 90 ° C, an extremely large amount of circulating nitric acid in the reaction system is required. If the temperature of the reaction zone is set to 90 ° C or lower, the consumption of nitric acid increases, the amount of air in the separation tower increases, and the general circulation of nitric acid aqueous solution containing generated dicarboxylic acid circulates in the system. There was a problem that the amount of reflux was large and the load on the crystallizer and the concentration tower increased. Also,

In order to maintain the alkanedicarboxylic acid yield even at a temperature exceeding 90 ° C, there was a problem that the amount of nitric acid circulated in the reaction system was enormous.

Disclosure of the invention

The object of the present invention is to solve the above-mentioned problems of the prior art, and to provide cycloalkanol and

In the method for producing alkanedicarboxylic acid by oxidizing Z or cycloalkanone with nitric acid in an adiabatic reactor, the circulation amount of nitric acid in the reaction system is more than necessary regardless of the temperature of the adiabatic reactor. Without increasing the amount of nitric acid, increase the yield of dicarboxylic acid, reduce the required amount of nitric acid, reduce the amount of air in the separation tower, reduce the large circulation flow rate of the aqueous nitric acid solution, It is an object of the present invention to provide a method capable of reducing the load on a concentration tower.

In oxidizing nitric acid to cycloalcohol and Z or cycloalkanoic acid with nitric acid to obtain alkionic dicarboxylic acid, if the temperature at the outlet of the adiabatic reactor can be raised, the reaction solution at the outlet of the reactor In addition to the advantage that the amount of nitric acid used can be suppressed because the concentration of the produced carboxylic acid dicarboxylic acid in the solution can be increased, it is also supplied to the separation column described in Japanese Patent Publication No. 439-19529. The amount of air to be done can be reduced.

There are other advantages to being able to raise the temperature at the adiabatic reactor outlet. Generally, in the process of producing nitric acid by nitric acid oxidation of cycloalkanol and / or cycloalkanol, nitric acid aqueous solution containing the produced alkanedicarboxylic acid reacts with nitric acid necessary for the reaction. Contains a large excess of nitric acid. Therefore, the generation al After separating the produced carboxylic dicarboxylic acid from the aqueous nitric acid solution containing carboxylic dicarboxylic acid by crystallization and distillation, the excess nitric acid is concentrated and recovered and recycled. In this specification, this is defined as a large circulation flow of the aqueous nitric acid solution.

If the temperature at the outlet of the adiabatic reactor can be increased, the concentration of the produced acandicarboxylic acid in the reaction solution at the outlet of the reactor can be increased. The amount of nitric acid aqueous solution can be reduced, and as a result, the load on the crystallizer and the concentration tower can be reduced.

As a result of intensive studies, the inventor of the present invention has found that in a method for producing alkanedicarboxylic acid by oxidizing cyclaluminol and / or cyclacanone in an adiabatic reactor using nitric acid, Regardless of the reactor temperature, specific cycloalkanols and / or cycloalkanols can be used to increase the yield of aldicarboxylic acid without increasing both the amount of nitric acid circulated in the reaction system and the large circulation flow rate of the entire system. The inventors have found that the above problems can be solved by using a method of mixing canon and nitric acid, and have completed the present invention. That is, a first aspect of the present invention relates to a method for producing an alkanedicarboxylic acid by oxidizing a cycling alcohol and a cycling alcohol with an aqueous nitric acid solution. And a mixing nozzle for feeding the cycloalkanol and / or Z or cycloalkanone, which can feed the cycloalkanol and / or the cycloalkanol at a linear speed of 8 × 10 ² msec or more. The above method, comprising using an adiabatic reactor.

A second aspect of the invention is the method of the first aspect of the invention, wherein the outlet temperature of the adiabatic reactor is a temperature above 90 ° C.

In a third aspect of the present invention, the aqueous solution of nitric acid, the reaction product from the aqueous solution of nitric acid or Z or the aqueous solution of nitric acid with the aqueous solution of nitric acid, the aqueous solution of nitric acid and / or Alternatively, at a position where a fluid containing cycloalkanone flows for 2.5 seconds after leaving the mixing device, the radial temperature profile of the adiabatic reactor has a standard deviation of 1.5 ° C or less. The method according to the first or second aspect of the invention.

According to a fourth aspect of the present invention, the temperature profile in the radial direction of the adiabatic reactor is 1.5 ° C. or less at a position separated from the mixing device by the same distance as the radius of the adiabatic reactor. 4 is a method according to the first or second aspect of the invention, having a deviation. According to a fifth aspect of the present invention, the aqueous nitric acid solution, the reaction product from the liquid alcohol and Z or the non-aqueous nitric acid with the aqueous nitric acid solution, At a position where the fluid containing the unreacted material of the mouth Alnon has flowed out of the mixing device for 2.5 seconds, the radial temperature profile of the adiabatic reactor is 1.5. C or less, and the temperature profile in the radial direction of the adiabatic reactor is 1.5 ° C or less even at the same distance from the mixing device as the radius of the adiabatic reactor. The method according to any one of the first to fourth aspects of the invention, having a standard deviation of

According to a sixth aspect of the present invention, the nitric acid aqueous solution separates nitrogen oxide, nitrous oxide, nitrogen dioxide, and nitrous acid from the reaction mixture discharged from the adiabatic reactor after the nitric acid oxidation reaction, By evaporating the water produced in the adiabatic reactor from the reaction mixture, the reaction mixture is concentrated to a nitric acid concentration at a height substantially corresponding to the nitric acid concentration at the reactor inlet, and the concentrated reaction mixture is concentrated. The alkanedicarbonic acid is separated from a portion of the mixture, the nitric acid in the mother liquor is concentrated in another concentrating system, the mother liquor and the rest of the concentrated reaction mixture are combined, and the combined mixture is treated with fresh nitric acid. The method according to any one of the first to fifth aspects of the present invention, wherein the nitric acid aqueous solution is mixed with an aqueous solution and returned to the reactor.

According to a seventh aspect of the present invention, the cycloalkanol and Z or cyclohexanone are cyclohexanol and / or cyclohexanone, and the alkanedicarboxylic acid produced is adipic acid. The method according to any one of the first to sixth aspects of the invention.

According to the method of the present invention, the amount of nitric acid circulated in the reaction system is determined irrespective of the temperature of the adiabatic reactor in order to regulate the mixed state of the siccula alpinol and / or the siccap alrinone and the nitric acid aqueous solution. The alkanedicarbonic acid yield can be increased without increasing the large circulation flow rate of the entire system. Further, according to the method of the present invention, the required amount of nitric acid can be reduced, the amount of air in the separation tower can be reduced, and the load on the crystallizer and the concentration tower can be reduced.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic diagram of a mixing device in the method of the present invention. FIG. 2 is a schematic view of a mixing device in the method of the present invention.

FIG. 3 is a schematic diagram showing one embodiment of a reaction system, a crystallization system, and a concentration system when the method of the present invention is used engineering.

BEST MODE FOR CARRYING OUT THE INVENTION

In the present invention, cycloalkanol includes cyclopentanol, cyclohexanol, methylcyclohexanol, cyclooctanol, and cyclododecanol.Cycloalkanones include cyclohexanone and methylcyclohexanol. Xanone and cyclododecanone.

Each of the above may be used alone as a raw material, or a mixture may be used as a raw material. In the present invention, the cycloalkanol is preferably cyclohexanol, and the cycloalkanone is preferably cyclohexanone. For example, a mixture of cyclohexanol and cyclohexanone may be used as a raw material, or only hexanol alone may be used as a raw material. These raw materials may remain as unreacted cycloalkanol and Z or cycloalkanone after the reaction.

In the present invention, the aqueous nitric acid solution refers to an aqueous solution having a nitric acid concentration of 10 to 70%, preferably an aqueous solution having a nitric acid concentration of 40 to 65%, and more preferably an aqueous solution having a nitric acid concentration of 50 to 65%. preferable. Here nitric acid concentration and the Al force Njikarubon acid and unreacted products of the product cycloalkanone Oyohizo or cycloalkanol excluding purely nitrate obtained from the amount of HN 0 ₃ and H ₂ 0 Concentration, that is, [HN 0 ₃ Z

(H ₂ 0 + HN 0 ₃ )].

In the present invention, the alkanedicarboxylic acid includes succinic acid, glutaric acid, adipic acid, and dodecanediic acid, and adipic acid obtained when cyclohexanol and / or cyclohexanone is used as a raw material is preferable. '

In the present invention, a method of mixing the cycloalkanol and Z or cycloalkanone with an aqueous nitric acid solution is important.

That is, in one method of the present invention, by using the fee Donozuru capable feed the cycloalk force Nord and z or cycloalk force Non at a linear velocity of 8 X 1 0- ² mZ seconds faster than, the cycloalk force Nord and / Or, feed the non-slip mouth. Another method of the present invention is to use a nitric acid aqueous solution and ぴ The use of a mixing device for mixing z or the ferrite non-alcohol.

FIG. 1 shows an example of the feed nozzles 1 and 2 of the nozzle and the nozzle. FIG. 1 shows two feed nozzles 1, which may be one or three or more. The tip of the feed nose ^ / may be a simple single tube with one hole, or the nozzle may have two or more holes. What is important is the linear velocity of the cycloalkanol and / or cycloalkanone 2 supplied from the feed nozzle.

In the present invention, the linear velocity of the cycloalpinol and / or cycloalkanone 2 refers to the linear velocity at the tip of the feed nozzle 1 of the cycloalpinol and Z or cycloalnonone 2, and 8 × 10 mZ seconds or more are preferred. It is more preferably at least 1 × 10 ¹¹ m / sec, and even more preferably at least 10 mZ seconds. In the present invention, the mixing device 3 refers to a normal mixer used for liquid-liquid mixing in the pipe 1 and includes a jet mixer, a static mixer, a Banbury mixer, an internal mixer, an orifice mixer, an impeller, and the like. However, a static mixer is preferred because of its simple structure and high mixing capacity. Various types of static mixers are described in Chemical Engineering Handbook, 6th revised edition, p. 452, Maruzen Co., Ltd. (199.99). May be used.

In the present invention, the number of the mixing devices 3 is not limited. That is, some of the mixing devices may be connected in series, or some of the mixing devices may be arranged in the nitric acid aqueous solution 4 in parallel. When the mixing devices are arranged in parallel, a feed nozzle may be provided only for a specific mixing device, or a common feed nozzle may be provided for these devices. However, it is preferable to provide the feed nozzles for each of the mixing devices. preferable. When arranged in series, the feed nozzles may be installed only in the first mixing device, or the feed nozzles may be individually installed in each of the mixing devices.

The interval between the feed nozzle 1 and the mixing device 3 may be apart, but the interval is preferably 10 mm or less, more preferably 5 mm or less. As shown in FIG. 2, the feed nozzle 1 is completely installed in the mixing device 3. It may be fully incorporated.

In the present invention, the ratio of the linear velocity of the cycloalcalonol and / or cycloalkanone 2 in the feed nozzle 1 to the linear velocity of the aqueous nitric acid solution 4 in the mixing device 3 is 1 × 10— It is preferably at least ² .

These aims at instantaneously mixing the cycloalcohol and / or cycloalcohol with the aqueous nitric acid solution, but a short mixing time alone is not sufficient. Feed nozzle of cycloalkanol and / or cycloalkanone it is important that the sheet click port al force Roh Ichiru及Pi / or consequent opening Al force Non be supplied in 8 X 1 0- ² m / sec or more.

In the present invention, the direction of the cycloalkanol and / or cycloalkanone feed nozzle is preferably close to parallel to the flow of the aqueous nitric acid solution. A T-tube may be used as the mixing device.However, using a static mixer as the mixing device, the feed nozzles of the siphon nozzle and Z or the siphon nozzle are arranged in parallel with the flow of the nitric acid aqueous solution. It is more preferable to install them. In any case, it is necessary to satisfy that the feed line speed of the nozzle and the feed line can be fed at a feed line speed of 8 × 10 to ² m / sec or more.

In the present invention, the aqueous nitric acid solution; the reaction product from the aqueous solution of nitric acid and Z or the aqueous product of nitric acid with the aqueous solution of nitric acid; the aqueous solution of nitric acid and Z or cycloalkanol; It is preferable that a fluid having a standard deviation of 1.5 ° C. or less is provided at a position where the fluid containing the unreacted substance flows for 2.5 seconds after leaving the mixing apparatus. Here, the standard deviation is represented by the following equation (1). η Σ Τ '(∑Τ):

(1)

η

η: Number of points for measuring temperature in the radial direction of the adiabatic reactor η≥10

T (° C): Temperature at each point in the radial direction of the adiabatic reactor

N in the above equation is a point for measuring the temperature. The interval between each measuring point is 5 mm or less. Measure the temperature from the reactor wall to the radially opposite wall at an interval of 5 mm or less. Therefore, if the device has a diameter of 100 mm, the temperature measurement point will be 21 points. For example, when the diameter of the adiabatic reactor is 10 O mm, the aqueous nitric acid solution, the reaction product of the cycloalternol and Z or the cycloalternative alcohol with the aqueous nitric acid solution, If the flow rate of the fluid containing the unreacted material of the metal and / or the nozzle is 0.6 m / hr and n is 21, the fluid flows from the mixing device for 2.5 seconds. The position is a position separated by 53 mm from the mixing device. That is, if the mixing device is a jet mixer, a static mixer, a bumper mixer, an internal mixer, an orifice mixer, an impeller, etc., the position of the mixing device is 53 mm from the position where the fluid exits. It is a position separated only by.

At that position, measure the temperature of the radial profile at the measurement point 21.

If the mixing device is a T-shaped tube injector, the starting point at a position 2.5 seconds away from the mixing device is the feed nozzle of the siphon mouth and the feed nozzle of Z or the sieve mouth. On the downstream side of the flow of the aqueous nitric acid solution.

When the standard deviation exceeds 1.5 ° C., a portion where the temperature is locally increased is formed, and the yield of aldicarboxylic acid is reduced. In the method for producing alkanedicarboxylic acid by oxidizing sucrose alkanol and Z or succulcan alkanone using nitric acid, if the reaction is a sequential reaction and the first half of the sequential reaction is a low temperature and the second half is a high temperature, The selectivity of the alkane dicarboxylic acid is improved. Moreover, the reaction is exothermic. If the standard deviation of the radial temperature profile of the adiabatic reactor is 1.5 ° C or less, the temperature rises from the inlet to the outlet of the thermal break reactor, so that the above-mentioned sequential reaction cannot be performed. An ideal flow direction temperature profile is obtained. Conversely, if the standard deviation exceeds 1.5 ° C., a portion having a high temperature is formed in the reactor, and the selectivity, that is, the yield, decreases. .

In the present invention, a fluid containing the aqueous nitric acid solution, a reaction product of the cycloalkanol and / or cycloalkanol with the aqueous nitric acid solution, and a non-reacted product of the cycloalkanol and / or cycloalkanol are used. As described above, the temperature profile in the radial direction of the adiabatic reactor at a position where it flows for 2.5 seconds after leaving the mixing device has a standard deviation of 1.5 ° C or less, as described above. Some of the mixing devices may be arranged in parallel. Several such mixers are placed in a reactor with a diameter of several meters. By installing the mixing devices in parallel, the temperature profile in the radial direction of the adiabatic reactor at a position 2.5 seconds away from the mixing device can be flattened.

Also, in the present invention, the aqueous solution of nitric acid, the reaction product of the aqueous solution of cycloallic acid and Z or the cycloaltic acid with the aqueous solution of nitric acid, and the unreacted product of the aqueous solution of cycloaltic acid and z or z or cycloalkanol are included. The mixing was performed so that the radial temperature profile of the adiabatic reactor at a position where the fluid flowed for 2.5 seconds after leaving the mixing device had a standard deviation of 1.5 ° C or less. A current plate may be provided at the outlet of the device. Examples of the current plate in the present invention include a perforated plate, a baffle tray, a lip tray, and the like which are usually used in a distillation column. The current plate may be in the immediate vicinity of the mixing device, may be several cm to several meters away, and may be two or more in the reactor. Is preferred. Even when two or more rectifying plates are provided, the temperature profile refers to the distribution at a position 2.5 seconds away from the mixing device.

In the present invention, the temperature profile in the radial direction of the adiabatic reactor may have a standard deviation of 1.5 ° C. or less even at the same distance from the mixing device as the radius of the adiabatic reactor. It is preferable to have

Also in this case, when the mixing device is a jet mixer, a static mixer, a pan parry mixer, an internal mixer, an orifice mixer, an impeller, or the like, the mixing device is located at a position where the fluid comes out. When the mixing device is a T-shaped tube, the mixing nozzle is located on the downstream side of the flow of the nitric acid aqueous solution at the siphon mouth nozzle and / or the feed nozzle.

Further, in the present invention, the aqueous nitric acid solution, the reaction product of the cyclo'alkanol and / or Z or cycloalkyrinol with the aqueous nitric acid solution, and the cycloalkanol and / or cycloalkanol At a position where the fluid containing the unreacted substance of the force flows for 2.5 seconds after leaving the mixing device, the temperature profile in the radial direction of the adiabatic reactor is 1.5 ° C or less. And the radial temperature profile of the adiabatic reactor is less than 1.5 ° C even at the same distance from the mixing device as the radius of the adiabatic reactor. With, it is more preferred. The standard deviation of the temperature profile in the present invention is important on a commercial scale when oxidizing cycloalcohol and / or Z-alcohol with a nitric acid aqueous solution to produce alkionic dicarboxylic acid. The standard deviation of the temperature profile is as small as 1 Omm in a so-called bench scale, so that even if a flow straightening plate is not used, or if several mixing devices are not arranged in parallel, 1 It is likely that the temperature will be lower than 5 ° C, but on a commercial scale, the above measures are required to keep the temperature below 1.5 ° C. Here, the commercial scale means a scale using an adiabatic reactor having a reaction tube diameter of 10 Omm or more, preferably 50 Omm or more.

The adiabatic reactor in the present invention refers to a purely adiabatic reactor described in “Industrial Reactor” edited by Kenji Hashimoto (Baifukan, 1984), pp. 25-26. A reactor is more preferable, but an intermediate heat exchange / multi-stage adiabatic reactor in which a heat exchanger is divided into several stages and a heat exchanger is provided between the stages to supply or remove heat may be used.

There is a method of producing an alkanedicarboxylic acid by oxidizing the cycling alcohol and Z or cycling alcohol using an aqueous nitric acid solution, and using an isothermal reactor. In this case, since the temperature is isothermal, the standard deviation of the temperature profile naturally becomes 1.5 ° C. or less. However, since the above-described sequential reaction proceeds at the same temperature, the selectivity for alkanedicarboxylic acid decreases. In addition, in the case of an adiabatic reactor, the amount of heat generated by the reaction can be used for the heat of concentration of nitric acid, but in the case of an isothermal reactor, a cooling system for removing the heat of the reaction is required. Heat for nitric acid concentration is required separately.

In the present invention, the outlet temperature of the adiabatic reactor is not particularly limited, but is preferably at least 80 ° C, more preferably at a temperature exceeding 90 ° C. A feed nozzle for the cycloalkanol and / or Z or Al-Non which can feed cycloalkanol and / or Al-Nin at a linear speed of 8 × 10-2 mZ seconds or more; If an adiabatic reactor including a mixing device is used, the temperature can be obtained even when the outlet temperature of the adiabatic reactor is preferably 80 ° C. or more, more preferably 90 ° C. or more. The alkanedicarboxylic acid yield is not reduced, but rather improved, compared to the prior art. Therefore, as described above, by setting the outlet temperature of the adiabatic reactor to a temperature of preferably 80 ° C. or more, more preferably 90 ° C. or more, the cycloalkanol And the amount of nitric acid consumed during the oxidation of z or cycloalkanone with nitric acid can be reduced, and the concentration of the produced carboxylic dicarboxylic acid in the reaction solution at the outlet of the adiabatic reactor can be increased. Therefore, the amount of the general circulation of the aqueous nitric acid solution containing the produced alkanedicarbonic acid circulating in the system can be reduced, and the load on the crystallizer and the concentration tower can be reduced.

For example, consider the case where the aldicarboxylic acid is adipic acid and the outlet temperature of the adiabatic reactor is 90 ° C or 75 ° C. To prevent precipitation of adipic acid in pipes and valves, if there is a margin of 10 ° C above the solubility, if the outlet temperature is 90 ° C, the solubility is 80. It can contain about 22 wt% of adipic acid equivalent to C, but at Ί5 ° C it can only contain a solubility of 65 ° C and about 15 wt% of adipic acid. Therefore, in order to obtain the same production of adipic acid, the amount extracted from the reaction system to the crystallization system, that is, the large circulation amount of the aqueous nitric acid solution, becomes 2 2/15 = 1.5 times. If the amount of the nitric acid aqueous solution is reduced, the load on the crystallizer and the concentration tower will be reduced. Furthermore, in a crystallizer, the higher the adipic acid concentration, the lower the energy required for crystallization.

Further, according to the method of the present invention, in order to maintain the yield of alkanedicarboxylic acid at a temperature at the outlet of the adiabatic reactor, preferably at least 80 ° C, more preferably at a temperature exceeding 90 ° C, There is no need to increase the amount of nitric acid circulated in the reaction system. In the conventional technology, when the reactor outlet temperature is set to a temperature exceeding 90 ° C, the weight ratio of the reaction system nitric acid circulation amount to the reaction component is set to 200 or more in order to maintain the alkanedicarboxylic acid yield. Had to be extremely large. A feed nozzle for mixing the cycloalkanol and Z or cycloalkanone with a linear velocity of 8 × 10 ¹² m / s or more, and a mixing nozzle for mixing the cycloalkanol and Z or cycloalkanone; If an adiabatic reactor including the apparatus is used, the weight ratio of the circulating flow of the reaction system to the reaction components is less than 200, and even if the temperature of the outlet of the adiabatic reactor exceeds 90 ° C. The acid yield can be increased.

In the present invention, after the nitric acid oxidation reaction, nitrogen oxide, nitrous oxide, nitrogen dioxide, and nitrous acid are separated from the reaction mixture discharged from the adiabatic reactor, and then, the thermal insulation reactor is separated. Concentrating the reaction mixture to a nitric acid concentration at a height approximately corresponding to the nitric acid concentration at the reactor inlet by evaporating the water formed therein from the reaction mixture; Separating the alkanedicarboxylic acid from a portion of the concentrated reaction mixture, concentrating the nitric acid in the mother liquor in a separate concentration system, combining the mother liquor with the remainder of the concentrated reaction mixture, The resulting mixture can be mixed with fresh aqueous nitric acid and returned to the reactor.

Here, the nitric acid concentration at a height substantially equivalent to the nitric acid concentration at the reactor inlet refers to, for example, a nitric acid concentration at the reactor inlet of not more than 1.5 Owt%.

The present invention will be described in detail with reference to the drawings showing an embodiment in which the method of the present invention is applied by engineering.

(31) in Fig. 3 is an adiabatic reactor. A nitric acid aqueous solution (32), which is a circulating flow of the reaction system, is sent from a lower part of the reactor (31) by a pump (33). Shikuroa Rukano one Honoré and / or consequent opening Al force than the feed can feed nozzle (34) in a non a linear velocity 8 X 10- ² m / sec faster than, cycloalk force non and / or consequent Roarukanonore (35) Feed Is done. The reaction system circulation stream (32) and the cycloalkanone and / or cycloalkanol (35) are instantaneously mixed by a mixing device (37) held by a holding plate (36). A perforated plate (38) is installed at a position several hundred mm from the outlet of the mixing device (37). The reaction product exiting the reactor (31) at a temperature higher than 90 ° C is introduced into the separation tower (39) and fed with air (40) to supply nitrogen oxide, nitrous acid, nitrogen dioxide, nitrous oxide. (41) are stripped. The stripped gas is absorbed by the absorption tower and recovered as nitric acid. In addition, between the separation tower (39) and the absorption tower, a facility for decomposing acetic acid nitrogen, which is a warming gas, may be provided. The reaction product exiting the separation tower (39) is fed to a nitric acid concentration tower (42). The nitric acid concentrating tower (42) is a pressure reducing tower, in which a part of the reaction heat is used for concentrating nitric acid. Drop water for recovery of nitric acid or washing water used in the subsequent crystallization step (49). The aqueous nitric acid solution (43) concentrated in the nitric acid concentrating tower (42) to a concentration substantially corresponding to the concentration in the reaction zone forms a reaction system circulation flow (32) by a pump (33). Further, a part of the bottom liquid (43) of the nitric acid concentration tower (42) is withdrawn from the reaction system, and goes through a crystallization step (44) to be a product (45). The mother liquor (46) coming out of the crystallization step (44) is concentrated through another concentration step (47) to form a general circulation stream (48). The The general circulation stream (48) is mixed with the reaction system circulation stream (32). Fresh nitric acid (50) is fed at the inlet of the adiabatic reactor to keep the concentration of nitric acid in the aqueous nitric acid solution circulating in the reaction system constant.

The alkanedicarboxylic acid remaining without being separated is contained in the aqueous nitric acid solution of the circulation stream (32) and the large circulation stream (48) of the reaction system. The concentration of the alcohol dicarboxylic acid contained in the aqueous nitric acid solution is 5 to 40%, but if the concentration is too high, the solubility becomes higher than the saturation solubility, and the nitric acid is used for the purpose of preventing the precipitation of crystals in pipes and relay tanks. Since the aqueous solution needs to be heated, 5 to 30% is preferable.

In the present invention, the outlet temperature of the adiabatic reactor can be preferably set to 80 ° C. or higher, more preferably to a temperature exceeding 90 ° C., so that the reaction system circulating nitric acid aqueous solution and the large circulating nitric acid aqueous solution can be used. It is possible to increase the concentration of the alkanedicarboxylic acid contained.

Next, the present invention will be described with reference to Examples and Comparative Examples.

Hereinafter, the mixing time is the same, and if the cycloalkanol and Z or is a reaction product had been fed cycloalk force non at a linear velocity of 8 X 1 0- ² m / ⁷ seconds faster than the following it Let's compare the yield of alkanedicarboxylic acid when fed at linear velocity. Here mixing time, phenolphthalein when mixed with N a OH and H ₂ SO ₄ as a tracer, refers to the time until the color of phenolphthalein disappears.

In the following, the aqueous nitric acid solution, the reaction product of the cycloalkanol and / or cycloalkanol with the aqueous nitric acid solution, and the unreacted product of the cycloalkanol and z or cycloalkanol The position where the fluid containing for 2.5 seconds has flowed out of the mixing device is simply referred to as the position of 2.5 seconds.

Example 1

A reactor having a length of 686 mm including a static mixer having a mixing section of 19 lmm using four elements of a Noritake static mixer having an inner diameter of 3 O mm was prepared. 0.04 N NaOH colored with phenolphthalein was flowed into the static mixer. As shown in Fig. 1, two feed nozzles with an inner diameter of l mm were installed immediately before the static mixer, and 1 N from the feed nozzle. The H ₂ S 0 ₄ was fed. The distance until the color of the phenolphthalein disappeared was converted to time, and this was defined as the mixing time. The Na OH 0. 95 [1 i / hr], was determined to 11 ₂ 3_Rei ₄ 102 [1 it / hr] in liquid passage and the mixing time, 1. was 1 second.

Next, nitric acid oxidation of cyclohexanol was performed using the same static mixer and feed nozzle. That is, a nitric acid aqueous solution containing 73.8 ° C and 54.6 wt% containing 0.5 wt% of Cu and 0.05 wt% of V was passed through the static mixer at 133 kgZhr, and the feed nozzle was Then, cyclohexanol was fed at 0.9 kg Z hr for 5 hours. The temperature at the outlet of the reactor was 91.8 ° C. The mixing time at this time was 1.1 seconds, and the linear velocity of cyclohexanol was 0.17 m / s. The liquid at the outlet of the reactor was sampled and the yield of adipic acid was measured. The result was 94. lmo 1% of the theoretical value. Nitrate consumption at this time was 0. '967 kg-HN_〇 ₃ Zk g- adipic acid. When the temperature profile was measured at a position 15 mm from the mixer, the standard deviation of the temperature was 0.50 ° C.

Comparative Example 1

A T-tube having an inner diameter of 16.1 mm and a length of 25 Omm was prepared as a mixing section, and a reactor including a T-tube and having a length of 65 Omm was prepared. 0.004N NaOH colored with phenolphthalein was introduced into one of the T-shaped tubes at 0.738 [1 itr]. The other from 1 N H ₂ S_〇 ₄ was fed at 1 1 5 [1 it / hr ]. The distance until the color of the phenolphthalein disappeared was converted to time, and the mixing time was determined to be 1.1 seconds.

Next, nitric acid oxidation of cyclohexanol was performed using the same T-tube. That is, a 75.6 ° C, 55.0 wt% aqueous nitric acid solution containing 0.5 wt% of Cu and 0.05 wt% of V was passed through the T-tube at 150 kg / hr, Cyclohexanol was fed from the feed nozzle at 0.7 kg / hr for 5 hours. The outlet temperature of the reactor was 91.0 ° C. The mixing time at this time was 1.1 seconds, and the linear velocity of cyclohexanol was 0.001 m / sec. The liquid at the outlet of the reactor was sampled, and the relative molar yield of adipic acid was measured to be 91.6 m 01%. The nitric acid consumption at this time was 1.018 kg-HNOg / kg-adipic acid. Moreover, when the mixer was measured temperature profile at the position of 8 mm, the standard deviation of temperature was 0. 90 ^D C.

The same average temperature as in Example 1, but the same mixing time, since Comparative Example 1 is the linear velocity of Kisano Ichiru cyclohexenone is less than 8 X 10 _ ² m / sec, adipic acid yield is poor. Example 2

Using a T-tube with an inner diameter of 10 mm and reducing only the inner diameter on the feed side of cyclohexanol to 2 mm, the mixing time was determined in the same manner as in Comparative Example 1, and it was 1.1 seconds. Was.

Next, nitric acid oxidation of cyclohexanol was performed using the same T-tube. That is, a 78.1 ° C, 55.3 wt% nitric acid aqueous solution containing 0.5 wt% of Cu and 0.05 wt% of V was passed through the T-tube at 132 kgZir, and the feed nozzle was Hexanol was fed at 0.9 kg / hr for 5 hours. The outlet temperature of the reactor was 91.3 ° C. The mixing time at this time was 1.1 seconds, and the linear velocity of cyclohexanol was 0.09 mZ seconds. The liquid at the outlet of the reactor was sampled, and the relative molar yield of adipic acid was measured to be 94. Omo 1%. Nitrate consumption at this time was _{0. 968 k g-HN0 3 /} kg- adipic acid. When the temperature profile at 5 mm from the mixer was measured, the standard deviation of the temperature was 0.70 ° C. The standard deviation of the temperature at 2.5 seconds from the mixer was 0.50 ° C.

In the mixing device of the same T-shaped pipe type as Comparative Example 1, the same average temperature, but a mixing time, since the second embodiment the linear velocity of hexanol Sik port is 8 X 10- ² m / sec or more, adipic The acid yield was as high as in Example 1. .

Example 3

The static mixer having an inner diameter of 12mm and mixing unit, length including the static mixer of H ₂ S_〇 ₄ of 1 N reactor 700mm flows at 99 [1 it / hr]. Immediately before the static mixer, two feed nozzles with a hole of 1 mm in diameter were installed, and 0.004N NaOH colored with phenolphthalein was fed at 0.967 [1 it / hr] with the feed nozzle. did. Same as Example 1 When the mixing time was determined by the same method, it was 0.07 seconds.

Next, nitric acid oxidation of cyclohexanol was performed using the same static mixer and feed nozzle. That is, a 78.4 ° C, 55.3 wt% aqueous nitric acid solution containing Cu 0.5 wt% and V0.04 wt% is fed into the static mixer at 130 kg / H, and Cyclohexanol was fed at 0.917 kg / hr. Therefore, the weight ratio of the circulation stream of the reaction system to cyclohexanol was 142. The mixing time was 0.07 seconds, and the linear velocity of the cyclohexanone was 0.17 m / ⁷ seconds. When the radial temperature profile was measured at a position 6 mm from the outlet of the static mixer, the standard deviation was 0.60 ° C. The temperature at the reactor outlet at this time was 91.2 ° C.

The gas at the outlet of the reactor was introduced into the separation tower, and nitrogen oxide, nitrogen dioxide, nitrous oxide, and nitrous acid were air stripped in the separation tower, and then concentrated in the concentration tower. The temperature at the bottom of the enrichment tower was about 80 ° C, and the concentration of adipic acid in the aqueous nitric acid solution discharged from the bottom was 21 wt. / ₀ . A part of the aqueous nitric acid solution was extracted out of the system, and the remaining aqueous nitric acid solution was returned to the reactor as a circulation stream of the reaction system. The obtained adipic acid had a yield of 96.2 wt% based on the theoretical value. Fresh nitric acid was added so that the nitric acid concentration at the reactor inlet was 55.3 wt%. Nitric acid consumption per adipic acid was 806 [kg / T-adipic acid].

Comparative Example 2

And injector mixing portion having an inner diameter of 1 lmm, length containing the injectors of 1 N reactor 80 Omm H ₂ S 0 ₄ was flowed at 99 [1 it / hr]. 0.004N NaOH colored with phenolphthalein was fed from the injector at 0.503 [1 it / hr.]. When the mixing time was determined in the same manner as in Example 1, the mixing time was 0.05 seconds.

Next, nitric acid oxidation of cyclohexanol was performed using the same injector. That is, an aqueous nitric acid solution at 60 ° C. and 60 wt% containing 0.5 wt% of Cu and 0.04 wt% of V was introduced into the reactor containing the injector at 130 kg / H. The cyclohexanol dissolves in a clear manner after 0.05 seconds. Feed. At this time, the linear velocity of cyclohexanol was 0.002 m / sec. When the radial temperature profile at a position 6 mm from the injector was measured, the standard deviation was 0.70 ° C. The reaction mixture was removed from the reactor at 70 ° C and introduced into the reactor. After nitric oxide, nitrogen dioxide, nitrous oxide, and nitrous acid were stripped in the separation tower, they were sent to the concentration tower. The nitric acid concentration was concentrated to about 56 wt% in the concentration tower. The bottom temperature of the concentration tower was about 55 ° C, and the concentration of adipic acid in the aqueous nitric acid solution discharged from the bottom was 9 wt%. A part of the nitric acid aqueous solution was drawn out of the system, and the remaining nitric acid aqueous solution was returned to the reactor as a circulation stream of the reaction system. The obtained adipic acid was in a yield of 95.0 wt% with respect to the theoretical value. Fresh nitric acid was added so that the nitric acid concentration at the reactor inlet was 60 wt%. Nitric acid consumption per adipic acid was 840 [kg gT-adipic acid].

Compared to Example 2, the nitric acid consumption per adipic acid was higher due to the lower reaction temperature. The adipic acid yield was low despite the low reaction temperature and short mixing time. Furthermore, because of the low reaction temperature, the concentration of adipic acid in the aqueous nitric acid solution extracted from the bottom of the concentration tower to the crystallization system was low. In order to obtain the same amount of adipic acid as in Example 2, 21/9 = 2.3 times the amount must be extracted. This indicates that the load of the crystallization system in the commercial process and another enrichment system in the subsequent stage is increased. Comparative Example 3

A stainless steel continuous isothermal device containing Cu 0.5 wt%, V0.04 wt%, 110 ° C, 50 wt% nitric acid aqueous solution 130 kg / H 13 kg / H was mixed in a T-shaped tube with inner diameter of 13111111 and then supplied. At this time, the linear velocity of the hexanol hexanol was 0.0003 m / s, and the mixing time was 1.05 seconds. A part of the reaction mixture was withdrawn to the crystallization system, and a part was circulated to the reaction system. The weight flow ratio of the aqueous nitric acid solution circulating in the reaction system to the hexanol in the mouth was 1000. At this time, the adipic acid yield was 94.1 wt% with respect to the theoretical value. Nitric acid consumption per adipic acid was 807 [kg / T-adipic acid].

Compared with Example 2, the adipic acid yield was lower due to the lower linear velocity of cyclohexanol. Furthermore, since the circulation flow of the reaction system was 1000: 142, which is 7 times larger, the load on the reactor, circulation pump and piping was also increased by 7 times. Example 4

IN ₂ H ₄ was introduced into the static mixer having an inner diameter of 8 Omm at 123 m ³ / hr. Immediately before the static mixer, two feed nozzles each having two holes of 2.4 mm in diameter were installed, and 0.004 N NaOH colored with phenolphthalein at the feed nozzle was 1.2 m / hr. Feed. When the mixing time was determined in the same manner as in Example 1, the mixing time was 0.05 seconds.

In an adiabatic reactor with an inner diameter of 1000 mm and a height of 10000 mm, a nitric acid aqueous solution containing 70.5 ° C and 53.6 wt% containing Cu 0.5 wt% and V0.04 wt% was circulated. Feed at 780 TZH. Five static mixers with an inner diameter of 80 mm are installed in the adiabatic reactor in parallel with the flow of the nitric acid aqueous solution, and each mixer has two holes of 2.4 mm in diameter that are almost parallel to the flow of the nitric acid solution. Two feed nozzles were installed. Cyclohexanol was fed at 5.6 T / H from the feed nozzle. Therefore, the weight ratio of the circulation stream to the cyclohexanol was 138. The mixing time was 0.05 seconds, and the linear velocity of cyclohexanol was 18.3 m / s. A multi-hole plate was installed at a position 300 mm from the outlet of the static mixer. When the radial temperature profile was measured at a position 2.5 seconds from the outlet of the static mixer, the standard deviation was 1.00 ° C. The standard deviation at 500 mm from the outlet of the static mixer was also 1.00 ° C. At this time, the temperature at the outlet of the adiabatic reactor was 95 ° C.

The gas at the outlet of the reactor is introduced for desorption, etc., and nitrogen oxide, nitrogen dioxide, nitrous oxide, and nitrous acid are stripped in the desorption column, and then the nitric acid concentration in the concentration column with a top pressure of 20 KPa Was concentrated to about 40 wt%. The bottom temperature of the concentration tower was about 80 ° C., and the concentration of adipic acid in the aqueous nitric acid solution discharged from the bottom of the tower was 21 wt%. A part of the nitric acid aqueous solution was sent to the crystallization step, and the remaining nitric acid aqueous solution was returned to the adiabatic reactor as a circulation stream of the reaction system. The aqueous nitric acid solution extracted and sent to the crystallization process was crystallized and refined in the usual way to obtain adipic acid. The obtained adipic acid had a yield of 95.8 wt% with respect to the theoretical value. The mother liquor discharged from the crystallization step was concentrated in another concentration step and returned to the above-mentioned circulation stream of the reaction system. At this time, fresh nitric acid was added so that the nitric acid concentration at the inlet of the adiabatic reactor became 53.6 wt%. Nitric acid consumption per adipic acid It was 800 [kg gT-adipic acid].

Example 5

Except that the perforated plate is not installed, the reaction system circulated nitric acid aqueous solution at 77 ° C and 55. Owt% containing 5 wt% of Cu O and 0.04 wt% of V was used in exactly the same manner as in Example 4. The solution was fed at 780 TZH, and cyclohexanol was fed at 5.6 Ύ / H from the feed nozzle. When measuring the radial temperature profile at a position 2.5 seconds from the outlet of the static mixer, the standard deviation was 2.50 ° C, and the temperature at the outlet of the adiabatic reactor was 95 ° C. Was. The standard deviation at 500 mm from the outlet of the static mixer was 2.44 ° C. The resulting adipic acid had a yield of 95.5 lwt% of the theoretical value. Since the standard deviation was 1.5 ° C or more, the adipic acid yield was lower than in Example 4.

Example 6

Except that the inlet temperature of the adiabatic reactor is set at 68 ° C, the reaction system of 55. Owt% containing Cu 0.5 wt%, VO. The circulating nitric acid aqueous solution was fed at 78 OTZH, and cyclohexanol was fed at 5.6 TZH from the feed nozzle. When a radial temperature profile at a position 2.5 seconds from the outlet of the static mixer was measured, the standard deviation was 1.oo ° c, and the temperature at the outlet of the adiabatic reactor was 85 ° C. . The obtained adipic acid had a yield of 96.6 wt <½ with respect to the theoretical value, which was slightly better than that of Example 4. However, because of the lower temperature, the consumption of nitric acid was lower than that of Example 4. 83.4 compared to [kg nitrate ZT adipic acid]. Further, the gas at the outlet of the reactor is introduced into the separation or the like, and nitrogen oxide, nitrogen dioxide, nitrous oxide, and nitrous acid are air stripped in the separation tower. The nitric acid concentration was concentrated to about 40 wt%. The temperature at the bottom of the concentration tower was about 70 ° C, and the concentration of adipic acid in the aqueous nitric acid solution discharged from the bottom was 15 wt%. Since the concentration of adipic acid was lower than that in Example 4, the general circulation amount of the aqueous nitric acid solution in the reaction system was 1.4 times that in Example 4, and the load on the subsequent crystallizer was also 1.4 times larger.

Comparative Example 4

A T-tube with an inner diameter of 2.9 mm and a length of 250 mm, including a T-tube. A reactor having a length of 65 Omm was prepared. The distance until the color of the phenolphthalein disappeared was converted to time in the same manner as in Comparative Example 1, and the mixing time was determined to be 0.01 second.

Next, using the same T-tube, the nitric acid reaction of cyclohexanol was performed. That is, a 78.4 ° C, 55.0 wt% aqueous nitric acid solution containing 0.5 wt% of Cu and 0.05 wt% of V was passed through the T-tube at 150 kg / hr. Cyclohexanol was fed from the feed nozzle at 0.7 kg / hr for 5 hours. The outlet temperature of the reactor was 91.0 ° C. At this time, the mixing time was 0.01 seconds, and the linear velocity of hexanol hexanol was 0.03 mZ seconds. The liquid at the outlet of the reactor was sampled, and the amount of adipic acid was 94.7% by weight based on the theoretical value. The nitric acid consumption at this time was 0.9915 kg—HN〇 ₃ / kg—adipic acid. When the temperature profile was measured 2.5 seconds from the mixer, the standard deviation of the temperature was 0.80 ° C.

Although the mixing time was faster than in Example 3, Comparative Example 4 had a poor adipic acid yield because the linear velocity of the hexanol in the mouth was 8 × 10 ¹² mZ seconds or less.

table 1

KA-Oil: cycloalkanone and / or cycloalkanol

Example 3 Comparative Example 2 Comparative Example 3 Inlet temperature [c] 78.4 60 Thermostat type reactor Outlet temperature [c] 91.2 70 Isothermal type reactor Average temperature [c] 84.8 65 1 10 Reactor diameter Lmm "12 11 Isothermal reactor anti-f core ¾f length Lmm ”700 800 Isothermal reactor Mixing device, static injector“ X ”tube mixer

Kinking device inner diameter LmmJ 12 11 13 Mixing time [sec] 0.07 0.05 1.05

KA-Oil Feet Inside Lmm "1 11 1 1

KA-Oil linear velocity [m / s] 0.17 0.002 0.0003

Acid concentration [wt%] 55.3 60.0 50.0

KA-Oil NOL NOL NOL ^ z

CLI; dragonness [wt%] 0.5 0.5 0.5

V concentration [wt%] 0.04 0.04 0.04 Nitric acid circulation amount [T / hr] 0.13 0.13 0.13

KA- Οί¾ Ckg / hr] 0.917 0.477 0.13 Nitric acid circulation rate KA-Oil [I] 142 273 1000

ADA yield 96.2 [wt%] 95.0 [wt%] 94.1 [wt%] Sodium acid consumption [kg nitric acid / T-ADA] 806 840 807 ADA concentration at reaction system outlet [wt%] 21 9 30 No perforated plate

Temperature standard deviation at 2.5 seconds [° C] 0.50 0.55

Temperature standard deviation at the same distance as the radius [° c] 0.60 0.70

KA-Oil: cycloalkanone and / or cycloalkanol

table 1

KA-Oil: Cycloalkanone and / or Cycloalkanol Industrial Applicability

According to the method of the present invention, a method for producing an alkanedicarboxylic acid by oxidizing a cycloalkanol and / or a cycloalnonone with nitric acid in an adiabatic reactor using nitric acid, Regardless of the temperature of the reactor, increase the alkanedicarboxylic acid yield, reduce the required amount of nitric acid, and reduce the amount of air in the desorption tower without increasing the circulation flow rate of nitric acid in the reaction system more than necessary. However, the large circulation flow rate of the nitric acid aqueous solution can be reduced and the load on the crystallizer and the concentration tower can be reduced.

Claims

The scope of the claims

1. A method for producing an alkanedicarboxylic acid by oxidizing a cycloalkanol and / or a cycloalkanol using an aqueous nitric acid solution, wherein the cycloalkanol and / or the cycloalkanol is Including a feed nozzle and / or a feed nozzle for the siphon Al-Non capable of feeding the non-linear SiN at a linear speed of 8 × 10-2 m / s or more, and a mixing device. The method as described above, comprising using an adiabatic reactor.

2. The method according to claim 1, wherein the outlet temperature of the adiabatic reactor exceeds 90 ° C.

3. reacting the aqueous solution of nitric acid, the reaction product from the aqueous solution of nitric acid and / or the aqueous solution of nitric acid with the aqueous solution of nitric acid, and the aqueous solution of alcohol and / or the aqueous solution of alkanone The temperature profile in the radial direction of the adiabatic reactor has a standard deviation of 1.5 ° C. or less at a position where the containing fluid has flowed for 2.5 seconds after leaving the mixing device. Item 1. The method according to item 1 or 2.

4. The radial temperature profile of the adiabatic reactor has a standard deviation of 1.5 ° C. or less at the same distance from the mixing device as the radius of the adiabatic reactor. Or the method described in 2.

5. It contains the aqueous nitric acid solution, a reaction product from the cycloalkinol and / or cycloalkanone and the aqueous nitric acid solution, and an unreacted product of the cycloalkanol and / or the cycloalkanol. At a position where the fluid flows for 2.5 seconds after leaving the mixing apparatus, the radial temperature profile of the adiabatic reactor has a standard deviation of 1.5 ° C or less, and The radial temperature profile of the reactor has a standard deviation of 1.5 ° C or less even at the same distance as the radius of the adiabatic reactor from the position where the mixing device exits. The method according to any one of claims 1 to 4.

6. The nitric acid aqueous solution separates nitric oxide, nitrous oxide, nitrogen dioxide, and nitrous acid from the reaction mixture discharged from the adiabatic reactor after the nitric acid oxidation reaction, and then, in the adiabatic reactor. By evaporating the formed water from the reaction mixture, the reaction mixture is concentrated to a concentration of nitric acid at a level substantially corresponding to the concentration of nitric acid at the reactor inlet, and the alkane is removed from a part of the concentrated reaction mixture. Separating dicarboxylic acid and mother The nitric acid in the liquid is concentrated by another concentrating system, the mother liquor is combined with the remainder of the concentrated reaction mixture, the combined mixture is mixed with fresh aqueous nitric acid, and the nitric acid returned to the reactor The method according to any one of claims 1 to 5, wherein the method is an aqueous solution.

7. The method according to claim 1, wherein the cycloalkanol and Z or cycloalnonone are cyclohexanol and / or cyclohexanone, and the alkanedicarboxylic acid produced is adipic acid. Item 7. The method according to any one of Items 1 to 6 above.